Stock flow control means for extruders and the like

ABSTRACT

A control assembly for extruders and the like in which stock is fed to the extruder at a substantially constant rate, passing through the outlet end into die members to form the plastic product defined by the mold members. The extruder head is provided with an additional outlet port for forming a skim along the interior surface of the product being formed which requires a cut-off of stock flow at periodic intervals. Rotatable means are provided for selectively diverting a portion of the main stock flow to be introduced into an opening within an extrusion die member so as to be diverted therethrough and passed through a central opening which communicates with an associated outlet opening provided in the extruder die head to form the skim layer. The control means comprises an axially rotatable plug member which, in a first angular position, provides for cut-off of the central stock flow while in a second position permits the main stock flow to be diverted therethrough and to enter into the extruder central opening. The control means, which is preferably a piston-driven structure, is loosely linked to the plug means so as to prevent any jarring or misalignment of the plug member while at the same time providing rapid and positive on/off action of the control means.

United States Patent [1 1 Cini [451 July 3,1973

[ STOCK FLOW CONTROL MEANS FOR [73] Assignee: Acme-HamiltonManufacturing Corporation, Trenton, NJ.

[22] Filed: July 13, 1971 [21] Appl. No.: 162,151

[52] US. Cl. 425/113, 425/110, 425/131,

' 425/133, 425/376 [51] Int. Cl B291 3/10 [58] Field of Search 425/109,145, 369,

[5 6] References Cited Primary Examiner-J. Spencer Overholser AssistantExaminerBrian P. Ross Attorney-Samuel Ostrolenk et al.

[57] ABSTRACT A control assembly for extruders and the like in whichstock is fed to the extruder at a substantially constant rate, passingthrough the outlet end into die members to form the plastic productdefined by the mold members. The extruder head is provided with anadditional outlet port for forming a skim along the interior surface ofthe product being formed which requires a cut-off of stock flow atperiodic intervals. Rotatable means are provided for selectivelydiverting a portion of the main stock flow to be introduced into anopening within an extrusion die member so as to be diverted therethroughand passed through a central opening which communicate s with anassociated outlet opening provided in the extruder die head to form theskim layer. The control means comprises an axially rotatable plug memberwhich, in a first angular position, provides for cut-off of the centralstock flow while in a second position permits the main stock flow to bediverted therethrough and to enter into the extruder central opening.The control means, which is preferably a piston-driven structure, isloosely linked to the plug means so as to prevent any jarringor'misalignment of the plug member while at the same time providingrapid and positive on/offaction of the control means.

10 Claims, 25 Drawing Figures PAIENTED JUL 3 I973 MEEBNS -mwmm -QNEPMENTED JUL 3 I973 dmwmm h QNE ATTORNEYS STOCK FLOW CONTROL MEANS FOREXTRUDERS AND THE LIKE BACKGROUND OF THE INVENTION.

This invention relates to extruder mechanisms and more particularly to anovel control means for controlling the flow of stock in extrudermechanisms so as to provide at least one intermittent stock flow withinthe extruder assembly which is extremely advantageous for use in formingcorrugated tubing and the like.

Corrugated tubing finds widespread use throughout a variety ofindustrial commercial and home applications. Typical corrugated tubingis comprised of an elongated corrugated section usually provided with asmooth cylindrical shaped cuff at each end thereof for connection withperipheral components. As one example, such corrugated tubing may haveone cuff coupled to the vacuum port of a vacuum cleaner with the cuff atthe opposite end being employed to couple vacuum cleaner accessoriesthereto such as, for example, brushes, nozzles and the like.

US. Pat. No. 3,280,430, issued Oct. 25, 1966 to Antrobus and assigned tothe assignee of the present invention describes an advantageous methodand apparatus for producing corrugated tubing which, briefly, iscomprised of consecutively forming two cuff sections for two separatebut connected sections of corrugated tubing, then forming a corrugatedsection of desired length. Thereafter, the same pattern is continuouslyrepeated. After the product is completed the corrugated tubes areseparated from one another by cutting at a point between the twoadjacent cuff sections which have been formed thereby separating eachcorrugated tube from the next. This technique and the apparatus.associated therewith is set forth in detail in the above identifiedpatent which is incorporated herein by reference thereto.

As further described in the above mentioned patent, it is advantageousin certain instances to provide a thin skin or interlayer within theinterior of the corrugated tubing so as to provide a relatively smoothinterior surface while at the same time retaining the resiliency andflexibility of the corrugated tube. In order to form the skim portion,the extruder assembly is provided with an additional outlet openingthrough which stock is emitted to form the skim along the interior peaksof the corrugated tubing. In forming corrugated tubing through theutilization of the apparatus described in the above mentioned patent, itbecomes necessary to terminate the flow of stock during those intervalsin which adjacent cuff portions are being formed. To date, no suitabletechnique has been developed prior to the advent of the presentinvention.

BRIEF DESCRIPTION OF INVENTION when rotated about its longitudinal axisto a first position, allows the stock to pass therethrough so as toenter into an axially aligned central opening where it passes throughthe extruder assembly to the outlet end at which point the stock passesabout an annular shaped guide member so as to form the skim referred tohereinabove.

By rotation of the plug member to a second position, the otherwisediverted stock flow is blocked from enteringinto the centrally locatedelongated opening so as to prevent the forming of the 'skim either incases where corrugated tubing with no skim is to be formed or duringthose intervals in which the cuff portions of the corrugated tubing arebeing formed. The plug member, while being very accurately fixed withinthe aforementioned transversely aligned opening, is loosely fittedto acoupling stern which provides sufficient play between the plugand stemmembers so as to prevent any damage or misalignment of the plug memberduring operation. A piston drive means is utilized for providing therotational actuation of the stock flow control means.

In an alternative embodiment, the axially rotatable plug means may bereplaced by a linearly reciprocating plug member which operates in asimilar fashion.

The extruder and control means may be advantageously employed forforming corrugated tubing with an internal skim wherein the extrudermeans is further provided with a conduit for introducing pressure intothe die members to facilitate even distribution of the emitted stockagainst the undulations of the die members.

It is therefore one object of the present invention to provide a novelstock flow control means for use in extruder assemblies and the like inwhich at least one particular stock flow conduit may be selectivelyoperated so as to either enable or interrupt stock flow therethrough.

Another object of the present invention is to provide a novel flowcontrol mechanism for use with extruders and the like employed to formcorrugated tubing in which the control mechanism intermittentlyinterrupts one stock flow conduit to selectively control the forming ofthe skim within the interior surface of the corrugated tubing beingformed.

Still another object of the present invention is to provide a novelcoupling mechanism for use with a stock The present invention iscomprised of an extruderasflow control means in which sufficient play isprovided between the plug means and its associated stem memher soas toprevent any misalignment of the plug means even after long andcontinuous operation thereof. i

BRIEF DESCRIPTION OF TI-IE FIGURES FIG. 1c is a top view, partiallysectionalized, showing the extruder assembly portion of the apparatus ofFIG. la.

FIG. 1:1 is an assembly drawing showing the detailed relationship of themanner in which the members of FIGS. 3, 4, 6, 7 and 9 are cooperativelyassembled.

FIG. 2a is a sectional view of the stationary male extrusion die memberof FIG. 1c.

FIG. 2b is an end view of the right-hand end of the die member shown inFIG. 2a.

FIG. 20 is a sectional view of the die member of FIG. 20 looking in thedirection of arrows BB'.

FIGS. 3a and 3b are side and end views, respectively, of the plug memberof FIG. 1b.

FIG. 4 is a side view of the stem member of FIG. 1b.

FIG. 5a is a sectional view of the extrusion pin member shown in FIG.1c.

FIG. 5b is a sectional view of the member of FIG. 5a looking in thedirection of arrows C-C'.

FIG. 5c is a sectional view of the member of FIG. 5a looking in thedirection of arrows D-D.

FIGS. 6a and 6b are side and end views, respectively, of the bushingseal shown in FIG. lb.

FIGS. 7a and 7b are side and end views respectively of the valve stembushing of FIG. lb.

FIGS. 8a and 8b are top plan and sectional views, respectively of theair cylinder pivot clevis of FIG. lb.

FIGS. 9a and 9b are side and top views, respectively, of the sternrotating arm of FIGS. la-ld.

FIGS. 10a and 10b are sectional and end views, respectively, showinganother preferred embodiment of the present invention.

FIGS. 10c and 10d are sectional and elevational views, respectively,showing a portion of the plunger of FIGS. 10a and 10b in greater detail.

DETAILED DESCRIPTION OF THE FIGURES FIGS. la-lc show the extruderassembly 10 of the present invention which is comprised of a femaleextrusion die member 11 having a central opening running through thelength of the member 11. The right-hand end is coupled to means forfeeding stock flow thereto and the opening consists of a tapered portion110 which narrows to a smaller diameter opening 11b which extendsthrough to the forward or left-hand end of the member relative to FIG.la. The left-hand end of female die member 11 is provided with a tappedopening 11c which threadedly engages the threaded right-hand end of aremovable die member 12 having an associated threaded portion 12a. Ascan best be 7 seen from FIGS. 1a and 1c, extrusion die member 12 has ahollow interior 12b of constant diameter running from its left-hand endtoward its right-hand end which hollow central opening communicates witha portion 12c of enlarged diameter, which enlarged diametersectionwidens to an inner diameter substantially equal to the. constantdiameter portion 1 lb of the opening in die member 11. Fitted into theinterior of extrusion die member 12 is an elongated extrusion pin member13, to be more fully described in detail in conjunction with FIGS.5a-5c. Elongated pin member 13 is aligned so as to be concentric withdie member 12 so as to form an elongated annular-shaped hollow interiorportion 14 gages the tapped portion 15a of a male extrusion die member15, to be more fully described in detail in conjunction with FIGS.2a-2c. Member 15 vis positioned within the opening Ila-11b of die member11 so as to be concentric therewith and so as to form an annularshapedhollow region 16 between the exterior surface of die member 15 and theinterior surfaces of openings 11a and 11b of die member 11. Die member11 is provided with an opening 11d which is aligned so as to beperpendicular to the longitudinal axis C of the assembly 10. A similaropening 15b aligned with opening 11d is provided within male extrusiondie member 15 as shown best in FIG. 10. This opening receives an axiallyrotatable plug member 17 to be more fully described in conjunction withFIGS. 10, 1d, 3a and 3b. As will be more fully described in connectionwith the operation of the stock flow control mechanism, plug member 17rotates about its longitudinal axis under the control of a piston drivemeans (to be more fully described) to control the flow of stockdownwardly (and upwardly) through opening 15b in male extrusion diemember 15 and through an axial opening provided in member 15 whichcommunicates with a central opening 13b provided in elongated pin member13 so as to selectively feed stock therethrough, which stock is emittedfrom the outlet end of the apparatus for use in a manner to be morefully described. By rotation of plug' member 17 to a second position,this stock flow may be halted when desired.

The right-hand end of plug member 17 is loosely mechanically linked to astem member 18 to be more fully described in conjunction with FIGS. 1dand 4, which member couples the rotation imparted to member 18 throughthe piston drive means (to be more fully described) to plug member 17.The right-hand end of stem member 18 passes through a hollow ring 19, abushing 20 and a bushing seal 21 (to be more fully described inconnection with FIGS. 1d and 6a-7b) and has its right-hand end linked toa stem rotating arm 22 to be more fully described in connection withFIGS. 9a and 9b. This linkage, as will be described, is by means of apin which is fitted through an opening provided in stem 18 and passesthrough a pair of cooperating openings provided in the stem rotating arm22. The opposite end of stem rotating arm 22 receives one end 23a of anair cylinder pivot clevis 23 which is provided with an opening 230 forthreadedly engaging the free end 24 of a piston shaft which is coupledthrough a piston shaft adapter 25 to an air cylinder 26. The lower endof air cylinder 26 (relative to FIGS. 1a and 1b) is prevented fromexperiencing any significant linear movement by means of pivot pin 27which threadedly engages an opening 28a provided within the air cylinderpivot plate 28. Opening 28a is tapped so as to threadedly engage thethreaded portion 270 of pin 27. A lock nut 29 is utilized to rigidlysecure pin 27 to pivot plate 28. The lower end of air cylinder 26 isprovided with a pair of projections 26a and 26b, each of theseprojections having elongated openings 26c, 26d (shown best in FIG. I.la) for receiving pin 27. As can clearly be seen from FIG. la, theopenings 26c and 26d provide for some limited linear movement of thepiston member relative to pivot pin 27 to assure proper alignment andoperation of plug 17. Collar 29 is provided for locking the air cylinderin position relative to pivot pin 27.

FIGS. 2a-2c show the stationary male extrusion die 15 of FIG. 10' ingreater detail. The left-hand end of member is provided with a threadedportion 15d which is fitted to an appropriate coupling (not shown) forconnecting male die 15 to an air pressure source. The central portion ofthreaded projection 15d is provided with an opening 15e which couplesthe incoming air pressure in common to a pair of conduits each havingdiagonally aligned conduit portions 15e-l5f and l5g-l5h. The right-handends of conduit portions 15f and 15h communicate with aligned openingsinelongated pin member 13, as will be more fully described. The diagonallyaligned paths formed by the conduits are provided so as to carry the airthrough die 15 without interfering with opening 15b.

The right-hand end of die 15 is provided with a recessed portion whichis tapped at'l5j so as to be threadedly engageable with a threadedportion provided at the communicating end of elongated pin 13, as willbe more fully described. A circular-shaped groove 15k is provided in thebase of the recess and is designed to communicate the air passingthrough conduits lSe-15f and 15g-15h to a pair of elongated openingsprovided through pin means 13 regardless of the relative alignmentbetween the openings in pin 13 and the openings 15l and 15m in die 15.

Opening 15b, which is aligned perpendicular to longitudinal axis of die15, is provided with a keyway portion l5n on one side thereof and hasits opposite surface communicating with an axially aligned opening 15pwhich, in turn, communicates with an axially aligned elongated openingprovided in pin 13, as will be more fully described. As can best be seenfrom FIG. 20, the upper portion of opening 15b (shown on the left-handend of FIG. 2c) is of slightly larger diameter as designated by numerallSq.

FIGS. 3a and 3b are side and end views respectively of the stock shutoffplug 17 which is a solid, substantially cylindrical shaped member havinga first end thereof provided with a spherically shaped surface 17a,-

while the opposite end thereof is provided with a substantiallyrectangular shaped projection 17b which links with a pair of bifurcatedarms provided on coupling stem 18 as will be more fully described. Plug17 is further provided with a cylindrical shaped opening 170 whichpermits the passage of stock therethrough and into opening 15p of maledie 15 in the following manner:

When plug 17 is rotated to an angular position wherein the longitudinalaxis 17d of opening 17c is aligned with longitudinal axis C of FIG. 10,a portion of the stock entering through the right-hand end of mem' ber11 is diverted so as to enter through both ends of the key-shapedportion l5n of male die 15 and passes through opening 170 so as to enterinto opening 15p where it then communicates with the central opening 13bin elongated pin 13 so as to pass through an extruder head in a mannerto be more fully described.

By rotating plug member 17 to an angular position whereby thelongitudinal axis 17d of opening 17c is aligned perpendicular to thelongitudinal axis C of FIG. 1c, any stock entering into key-shapedopening l5n is blocked from being passed through plug opening 17c andinto opening 15p due to the misalignment.

If desired, an alternative arrangement may be. provided in which theplug may be moved to an intermediate position whereby a portion ofopening 17c communicates with key way l5n and axial opening 15p so as topermit the passage of a limited amount of stock 6. therethrough. Thus,if desired, the plug may be altered from its primary use strictly as anon/off control, to use as a means for regulating stock flow therethroughto any amount between the extremes of being completely on and completelyoff.

Rotation of plug 17 is provided by means of the stem member 18 shown iiigreater detail in FIG. 4. The stock shutoff stem 18 is provided with apair of bifurcated arms 18a and 18b which embraces the projection 17btherebetween (Note also FIG. lb). The bifurcated arms are integrallyjoined to an elongated rod shaped portion 180 which passes throughopenings provided in members ll, 19, 20, 21 and 22 so as to be coupledto the rotatable stern arm 22 in a manner to be more fully described.The positive linkage between stem 18 and the arm 22 for rotating thestem is provided by means of a pin which passes through an opening 18din stem 18 and which further passes through a pair of diametricallyaligned openings provided in rotating arm 22, as will be more fullydescribed.

The opening 11d (note FIGS. 1a and 1b) in member 11 receives theleft-hand end of a valve stem bushing 20 shown best in FIGS. and 7b. Thevalve stem bushing is provided with an axially aligned opening 20ahaving a reduced diameter portion 20b. The cylindrical portion 200thereof is inserted within opening 11d and reduced diameter portion 20bslidably receives the rod portion of stem 18 which extends throughoutthe entire axial opening of bushing 20 but makes slidable engagementwith only the reduced diameter portion 20b. Cylindrical shaped portion200 is threaded. at 20d so as to threadedly engage opening 11d which issuitably tapped so as to firmly secure valve stem bushing 20 withinmember 11..The right-hand portion 20s of bushing 20 is of a hexagonalshape, as can clearly be seen from FIG. 7b. A portion 20f of enlargeddiameter opening 20a is tapped so as to threadedly engage a threadedportion provided on bushing seal member 21. Bushing seal member 21 isshown best in FIGS. 6a and 6b, and is comprised of a cylindrical shapedportion 21a and a hexagonal shaped portion 21b. The portion 210 of thecylindrical portion of bushing 20 is threaded so as to threadedly engagetapped portion 20f of valve stem bushing 20. The left-hand edge 21d ofbushing seal 21 cooperates with a shoulder 203 provided in valve stembushing 20 (Note FIG. 7a) to embrace a seal ring 19 to be more fullydescribed in connection with FIG. 4d.

FIGS. 9a and 9b are side and end views respectively of the arm 22 forrotating stem 18. The stem rotating arm 22 is comprised of an armportion 22a having a first opening 22b at its narrower end for receivingthe rod shaped portion 23a of the air cylinder pivot clevis 23, to bemore fully described. The wider end of arm 22a is provided with anopening 22c which extends through arm portion 22a and circular shapedcollar,

portion 22d. Collar portion 22d is provided with a pair of openings 22eand 22f which are aligned so that their axes are colinear with phantomline 22g (i.e., so that they are diametrically opposite one another).The openings are provided for receiving a fastening pin (not shown)which passes through the opening 18d in stem 18 (See FIG. 4) andopenings 22e and 22f to positively link arm 22 to stem 18.

FIGS. 8a and 8b are end and sectional views respectively of the aircylinder pivot clevis 23 which is comprised of a cylindrical shapedportion 23a integrally joined to a hollow cylindrical shaped portion 23bhaving a smaller diameter opening 23c which is threaded along its lengthand which communicates with a larger diameter opening 23d. Thelongitudinal axis 23c of openings 23c and 23d is aligned perpendicularto the longitudinal axis 23f of cylindrical shaped portion 23a.Cylindrical shaped portion 23a extends through opening 22b provided inrotating arm 22 while tapped portion 23c threadedly engages the threadedportion 24a of piston arm 24.

FIG. 1d is a side view, partially sectionalized, showing the components18-22 respectively. As can be seen,

' projection 17b in plug 17 is fitted between the bifurcated arms 18aand 18b of stem 18. The rod portion 18c thereof extends through theopening in member 11 (See FIGS. 1a and 1b) and further extends throughthe central opening provided in member 20. The tapped portion 20f ofmember 20 threadedly engages the threaded portion 21c of member 21. Theleft-hand edge 21d of member 21 and the shoulder 20g of member 20 act toembrace a sealing ring 19 therebetween. The right-hand end of the rodportion 180 of stem 18 extends beyond the central opening in member 21and into the opening 22c provided in rotating arm 22. The opening 18d instem 18 is aligned with the pair of openings 22c and 22f in rotating arm22 and a fastening pin is inserted therethrough so as to positively linkstem 18 to rotating arm 22.

The air cylinder 26 is provided with an air driven piston (not shown)which is mounted for reciprocal operation within the air cylinderhousing so as to move either' upwardly or downwardly (relative to FIG.1b) as shown by arrows D and D respectively. Suitable openings (notshown) are provided in air cylinder housing for coupling with a suitablesource of air pressure for operating the piston upwardly and downwardlyto move arm 22 and thereby rotate stem 18 and plug 17 to the on and offpositions as was described hereinabove. Although the preferredembodiment described herein utilizes an air cylinder for actuation ofthe on/off plug member 17, it should be understood that any othersuitable actuating mechanism may be employed such as, for example, arelay or any other electromechanical or mechanical device.

It should be noted that no coupling mechanism is provided between plug17 and stem 18 and that a limited amount of play is provided betweenthese members so as -to prevent any misalignment of stem 18 from causingany misalignment or jamming of plug member 17 which is the only memberrequiring precise alignment. In spite of this play, there is sufficientdrive coupling between the members 17 and 18 so as to assure themovement of plug member 17 to the full on and full off positions.

The assembly of FIG. 1d thus acts to provide a means about which thestem 18 and hence the plug 17 may rotate while at the same timeproviding a seal which prevents the incoming stock from escaping throughopening 11d in member 11.

Turning to a consideration of FIGS. 1d, 2a-2c and a-5c, it can be seenthat the plug 17, when aligned in the manner described hereinabovepermits some of the entering stock to be diveretd through keyway l5n,opening 17c in plug 17 and opening p in die 15 so as to pass through theelongated axial opening 13b in elongated extrusion pin 13. As wasdescribed hereinabove, the left-hand end of pin member 13 relative toFIG. 5a is provided with a threaded portion 13a which threadedly engagesthe tapped portion l5j provided within the recess of member 15. Adjacentthe threaded portion 13a is an annular groove 13c which may be fittedwith an O-ring for preventing the egress of air fed through conduitsl5fand 15h, as well as preventing the egress of stock therethrough. Theannular flange 13d which lies immediately adjacent annular groove 13cfits within the annular shaped recess 15:; of member 15.

The elongated axial opening 13b is provided with a slightly enlargeddiameter portion 13c at its right-hand end (relative to FIG. 5a) whichportion is tapped so as to threadedly engage the threaded portion of anextruder head to be more fully described. The air conduits 15e-15f and15g-15h of male die 15 respectively communicate with a pair of elongatedconduits 13f and 13g provided within elongated pin 13 so as to pass theair under pressure through pin assembly 13 and into the extruder diehead coupled thereto for a purpose to be more fully described.

The left-hand ends of conduits 13f and 13g (relative to FIG. 5a) areprovided with bevelled portions 13h and l3j for communicating with theannular recess 15k provided at the base of the threaded opening 15j indie 15 which receives the threaded portion 13a of elongated pin assembly15.

The exterior surface portion 13k of pin 15 is provided with asubstantially square shaped configuration to facilitate insertion,tightening and removal of the pin member 13 when it becomes eitherdesirable or necessary to do so.

It can thus be seen that the extruder assembly provides three separateand independent flow conduits namely the axially aligned conduit 13b forthe flow of stock to form the skim mentioned hereinabove; the pair ofconduits 13f and 13g for the flow of air and the annular shaped hollowregion 14 which lies between the exterior surface of pin 13 and theinterior surface of extrusion die 12 for the flow of stock therethrough.

The extrusion die head 30 is shown best in the enlarged section of FIG.1c and is comprised of a threaded narrow diameter portion 304 whichthreadedly engages the tapped portion 13a of pin 13. Spaced inwardlyfrom portion 30a is a cylindrical shaped portion 30b which diverts thestock flowing out of hollow annular region 14 in the manner shown byarrows 31. The die head 30 is provided with a central opening 30c forpassing stock entering opening 30c, through a plurality of openings 30dso as to pass around an adjustable ring 30e and form the skim along theinterior peaks of the corrugated tubing being formed. Further elongatedopenings 30f and 303 are provided in extruder head 30 for communicatingwith the openings 13] and 133, respectively, of the elongated pin 13 tocouple the air passed therethrough with a plurality of spaced openings30!: to pass the air entering conduits 30g and 30f out of the die head30 and outwardly toward the corrugated tubing being formed. The flow ofair may be regulated by adjusting ring 30k which threadedly engages thethreaded surface 301 of the extruder die head to cover more or less ofthe openings 30):. Ring 30c also is tapped so as to be adjustable tocover more or less of the openings 30d.

As was described in the aforementioned U. S. Pat. No. 3,280,130, theextruder assembly 10 as shown and described in FIGS. la-lc isstationary. US. Pat. No. 3,280,130 describes the die molds as being madeup of die mold halves which are firmly pressed together to form acontinuous circular shaped die mold of a corrugated contour. The diemold sections, shown best in FIGS. 1, 2, 3, 7 and 8 of U.S. Pat. No.3,280,130, are designated by the numerals 41, 41, and more relative tothe extruder assembly 10 FIG. 10 of the instant invention in thedirection shown by arrow 31 of FIG. 1c. As the die mold halves move pastthe stationary extruder head assembly 30, the stock exiting from thehollow annular space 14 and designated by the arrows 31 enters into theundulations 32 of the die molds so as to form the corrugated tubing. Theair exiting from openings 30d acts to assist the stock flowing aboutcylindrical shaped member 30b to be firmly urged into the undulations ofthe die members.

The stock flow which passes through opening 300 exits through openings30h and flows around ring 30k in the manner shown by arrows 30. Thisstock flow forms the skim or web 36 along the interior peaks 35a of thecorrugated tubing 35 being formed within the die molds. The air conduits30f and 30g further communicate with openings 30m which serve to keepthe corrugated tubing being formed inflated so as to retain its shapeafter the die mold halves again separate in the manner shown best, forexample, in FIG. 1 of aforementioned U. S. Pat. No. 3,280,130. Tofacilitate this condition, the forward ends of the corrugated tubingbeing formed is preferably pinched off or, alternatively, a plug meansis provided for retaining pressure within the tubing being formed. Theair pressure is preferably quite low and is usually of the order of 3psi.

The Bauman et al. U.S. Pat. No. 3,430,292 describes in detail the mannerin which the cuff portions are formed using apparatus of the typedescribed hereinabove as well as that apparatus described in theaforementioned U. S. Pat. No. 3,280,130. This arrangement constitutesthe use of sections of die mold halves which have a smooth, cylindricalsurface so as to form in immediate sequential fashion the cuff portionsfor two separate corrugated tube sections (i.e., so as to form the endcuff portion for the last corrugated tubing section which has beenformed and so as to form the forward cuff portion for the corrugatedtubing section which is about to be formed). Since it is undesirable toform a skim upon the interior surface of these cuff portions, as thiswill cause a significant deviation in the interior diameter of the cuffportions, the plug means described hereinabove is utilized to terminatethe flow of stock during those intervals in which the cuff portions arebeing formed.

As another obvious alternative, the extruding assembly of the presentinvention may alternatively be employed to form the corrugated tubing inwhich it is desired to have no skim simply by operating the piston drivemeans to maintain indefinite cutoff of the flow of stock otherwiseutilized to form the skim layer.

Another embodiment 40 of the present invention which is comprised of astationary female extrusion die I member 41 which is somewhat similar tomember 1 l of FIGS. la-lc. Member 41 is provided with an axial opening41a for receiving a male die member 42 of substantially cylindricalshape and being comprised of a larger diameter portion 42a and a smallerdiameter I portion 42b being integrally a tapered portion 420.

Member 41 is provided with an elongated opening 41b whose central axis44 is perpendicular to the cenjoined to one another by tral axis 42 ofopening 41a. An elongated rod-shaped plunger 45 is fitted within opening44 and is adapted for reciprocal movement therethrough in the mannerindicated by double ended arrow 46. Member 41 is provided with aplurality of annular shaped grooves 410, each of which are fitted withO-rings 47 which provide a sliding seal between plunger 46 and opening41b to prevent the egress of any stock therethrough.

Theright-hand end of member 41 is provided with a pair of arcuate shapedgrooves 410 and 4ld which together with the narrow diameter portion 42bof member 42 form arcuate shaped openings to permit the passage of stocktherethrough in a manner to be more fully described.

As shown best in FIGS. c and 10d, plunger 45 is provided with a pair ofdiagonally aligned slots 45a and 45b. FIG. 10c shows a sectional view ofthe upper portion of plunger 45 in which slot 45a is shown as beingdiagonally aligned so as to provide an inlet opening 45d whichcommunicates with the hollow annular space 49 defined by the outersurface of member 42 and the interior surface (i.e. opening 410) ofmember 41. An outlet opening 450 is adapted to communicate with thearcuate shaped opening formed by groove 41c and the narrow diameterportion 42b of member 42.

The portion 41e of member 41 surrounding narrow diameter portion 42b ofmember 42 is joined to the outer portion 41f by webs 41g which dividethe otherwise continuous annular shaped hollow region 49 into aplurality of separate arcuate sections 49.

The operation of the flow control apparatus of FIGS. l0a-l0d is asfollows:

Stock enters from the left through opening 41a and passes through thehollow annular shaped region 49. With the plunger 45 in the dotted lineposition 45', it can be seen that the openings 45a and 45b are displacedfrom the hollow annular region 49 as well as from the arcuate regions41c and 41d so as to prevent the passage of any stock flow therethrough.This constitutes the cutoff position for stock flow through the outlets4lc and 41d.

By moving plunger 45 downwardly into the solid line position, openings45a and 45b communicate on the left with annular opening 49 and on theright with arcuate shaped openings 41c and 41d so as to permit some ofths stock entering into annular shaped region 49 to be diverted throughthe openings 45a and 45b and plunger 45 and thereby enabling the stockto pass through openings 41c and 41d.

Whereas plunger 45 does block portions of the annular shaped opening 49,it can clearly be seen that the stock flow is otherwise unimpeded as itis permitted to pass around each of the plunger portions impeding flow(in the regions A and B shown in FIG. 9b). After passing around plunger45 and outwardly through member 41, the stock flow becomes substantiallycontinuous and uniformand passes through an annular shaped othersuitable mechanical or electromechanical device. The apparatus of FIGS.a-10d may be utilized with an assembly of the type shown in FIGS. la-lcwhich is accordingly modified so as to communicate with the stock flowopenings provided in the embodiment of FIGS. 10a and 10b. Member 42 maybe provided with elongated openings 42f and 42g to provide air conduitswhich serve in a fashion similar to those described in conjunction withthe embodiment of FIGS. la-lc to perform the functions describedhereinabove.

It can be seen from the foregoing that the present invention provides anovel stock flow control means for use in extruders and the like inwhich separate stock flow conduits are provided to yield a continuousstock flow conduit and an intermittent stock flow conduit which may beutilized to open or close the intermittent stock flow conduit in a rapidand positive manner and which is especially advantageous for use informing the skim layer in corrugated tubing as was describedhereinabove. The stock flow control means utilizes a plunger memberwhose accurate positioning is maintained by providing a loose fittingactuating stem member which introduces sufficient play between the stemand plug members so as to prevent any misalignment or jamming of theplug member during continuous thereof.

In the foregoing this invention has been described in conjunction withpreferred embodiments. Many modifications will now become apparent tothose skilled in the art and it is preferred, therefore, that theinstant invention be limited not by the foregoing disclosure but only bythe appending claims.

What is claimed is:

1. Flow control means for extruders and the like comprising:

a first hollow die member;

a second annular shaped die member positioned within said first diemember and forming a hollow annular region defined by the interiorsurface of said' first member and the exterior surface of said secondmember;

means for feeding stock at a first end of said first and second membersinto said hollow annular region to exit at the second end thereof;

said first and second members each having coaxial openings whereby thecommon axis of said coaxial openings is transverse to said hollowannular shaped opening;

the opening in said first member having an elongated groove along thesurface of said opening and having at least one end thereofcommunicating with said hollow annular shaped region;

said second die member having an axial conduit coupling the opening insaid second die member with the second end of said second die member;

rotatable plug means mounted within the opening'in said second diemember and having an opening aligned transverse to the axis of rotationof said plug means;

control means extending into said coaxial openings and coupled to plugmeans for rotating said plug means between a first position wherein saidplug opening establishes a stock flow path for stock entering saidgroove through said plug opening and into said axial conduit and asecond position whereby said plug opening is offset from said axialconduit and said groove to prevent the flow of stock into said axialconduit.

2. The apparatus of claim 1 wherein said control means comprises arotatable stem member coupled to one end of said plug means wherebysufficient play is provided between said stem member and said plug meansto provide free movement of said plug means between said first andsecond positions while preventing axis-alignment or jamming of said plugmeans.

3. The apparatus of claim 2 wherein the end of said plug means isprovided with a pair of spaced substantially parallel faces;

said stem member having a pair of bifurcated arms loosely embracing saidparallel faces to impart rotational movement to said plug means.

4. The apparatus of claim 1 wherein said second die member is providedwith a second conduit extending between the first and second ends ofsaid second die member;

means for feeding air under pressure into the first end of said secondconduit means;

said second conduit means being completely isolated from the coaxialopening provided in said second die member.

5. The apparatus of claim 4 wherein said second conduit comprises a pairof conduits joined at the first end of said second die member extendingaround and isolated from said coaxial opening and terminating inseparate openings provided at the second end of said second die member.

6. The apparatus of claim 1 wherein said control means includes aircylinder means having a piston rod; a coupling arm coupled between saidpiston rod and said stem member for converting the linear movement ofsaid piston rod into rotational movement for rotating said plug means.

7. The apparatus of claim 6 further comprising bearing means providing asealed bearing assembly for said stem mbmer while preventing the escapeof stock from said first and second member coaxial opening.

8. Flow control means for extruders and the like comprising:

a first hollow die member;

a second annular shaped die member positioned within said first diemember and forming a hollow annular region defined by the interiorsurface of said first member and the exterior surface of said secondmember;

means for feeding stock at a first end of said first and second membersinto said hollow annular region to exit at the second end thereof;

said first and second members each having coaxial openings whereby thecommon axis of said coaxial openings is transverse to said hollowannular shaped opening; i

rod shaped means mounted within said opening;

second conduit menas communicating between one of said coaxial openingsand the second ends of said first and second die members;

at least one opening in said rod means;

means for moving said rod means between a first position for divertingstock passing through said hollow annular region through said opening insaid rod means and into said conduit means and a second position'whereby said rod means opening is displaced from said hollow annularregion and said 13 conduit to prevent the flow of stock into said con-10. The apparatus of claim 8 wherein said rod is mounted for rotationalmovement between said first 9. The apparatus of claim 8 wherein said rodis mounted for reciprocating movement between said and second 5' firstand second positions. I

1. Flow control means for extruders and the like comprising: a firsthollow die member; a second annular shaped die member positioned withinsaid first die member and forming a hollow annular region defined by theinterior surface of said first member and the exterior sUrface of saidsecond member; means for feeding stock at a first end of said first andsecond members into said hollow annular region to exit at the second endthereof; said first and second members each having coaxial openingswhereby the common axis of said coaxial openings is transverse to saidhollow annular shaped opening; the opening in said first member havingan elongated groove along the surface of said opening and having atleast one end thereof communicating with said hollow annular shapedregion; said second die member having an axial conduit coupling theopening in said second die member with the second end of said second diemember; rotatable plug means mounted within the opening in said seconddie member and having an opening aligned transverse to the axis ofrotation of said plug means; control means extending into said coaxialopenings and coupled to plug means for rotating said plug means betweena first position wherein said plug opening establishes a stock flow pathfor stock entering said groove through said plug opening and into saidaxial conduit and a second position whereby said plug opening is offsetfrom said axial conduit and said groove to prevent the flow of stockinto said axial conduit.
 2. The apparatus of claim 1 wherein saidcontrol means comprises a rotatable stem member coupled to one end ofsaid plug means whereby sufficient play is provided between said stemmember and said plug means to provide free movement of said plug meansbetween said first and second positions while preventing axis-alignmentor jamming of said plug means.
 3. The apparatus of claim 2 wherein theend of said plug means is provided with a pair of spaced substantiallyparallel faces; said stem member having a pair of bifurcated armsloosely embracing said parallel faces to impart rotational movement tosaid plug means.
 4. The apparatus of claim 1 wherein said second diemember is provided with a second conduit extending between the first andsecond ends of said second die member; means for feeding air underpressure into the first end of said second conduit means; said secondconduit means being completely isolated from the coaxial openingprovided in said second die member.
 5. The apparatus of claim 4 whereinsaid second conduit comprises a pair of conduits joined at the first endof said second die member extending around and isolated from saidcoaxial opening and terminating in separate openings provided at thesecond end of said second die member.
 6. The apparatus of claim 1wherein said control means includes air cylinder means having a pistonrod; a coupling arm coupled between said piston rod and said stem memberfor converting the linear movement of said piston rod into rotationalmovement for rotating said plug means.
 7. The apparatus of claim 6further comprising bearing means providing a sealed bearing assembly forsaid stem mbmer while preventing the escape of stock from said first andsecond member coaxial opening.
 8. Flow control means for extruders andthe like comprising: a first hollow die member; a second annular shapeddie member positioned within said first die member and forming a hollowannular region defined by the interior surface of said first member andthe exterior surface of said second member; means for feeding stock at afirst end of said first and second members into said hollow annularregion to exit at the second end thereof; said first and second memberseach having coaxial openings whereby the common axis of said coaxialopenings is transverse to said hollow annular shaped opening; rod shapedmeans mounted within said opening; second conduit menas communicatingbetween one of said coaxial openings and the second ends of said firstand second die members; at least one opening in said rod means; meansfor moving said rod means between a first position for diverting stockpassing through said hollow annular region through said opening in sAidrod means and into said conduit means and a second position whereby saidrod means opening is displaced from said hollow annular region and saidconduit to prevent the flow of stock into said conduit.
 9. The apparatusof claim 8 wherein said rod is mounted for reciprocating movementbetween said first and second positions.
 10. The apparatus of claim 8wherein said rod is mounted for rotational movement between said firstand second positions.